Motor-controlling apparatus.



s. 11. KBEPER. MOTOR GONTROLLING APPARATUS.

APPLIUATLON FILED PEB. 21, v1910.

1,003,269. Patented Sept. 12', 1911.

' a @anims-SHEET 1.

vlllllll S. H. KEEFER.

MOTOR CONTBOLLING APPARATUS.

APPLICATION FILED TERZI, 1910.

Patented sept. 12,1911.

3 BHEETS-BHBET 2.

S. H. KEEPER.

yMOTOR GONTROLLING APPARATUS.

APPLICATION FIL-ED TERZI, 1910.

Patented sept. 12,1911.`

3 SHEETS-SHEET 3.

UN 'STATES PATENT OFFICE.

SAMUEJL vELINE liiEEEER, 0E PLAINEIELE, NEW JERSEY, AssIefivoEv To NILEs-BEMENT- rom) QQMIEANY, 0E JERSEY CITY, NEW JERSEY, A CORPORATIONl 0E NEW JERSEY.

MOTOR-CONTROLLING APPARATUS.

'.'o all whom tt'may concern:

Be it known that I, SAMIE'L H. KEEFER, a citizen ofthe United States, and a resident of Plainfield, New Jersey, have invented rtain Improvements in Motor- Controlling Apparatus, of which the fol lowing is a specification.

My invention relates to that class of ap# paratus especially designed to control 'the current flow to an electric motor, in which the main motor controlling switchesv are governed by electromagnetic means such as solenoids, the energization of whosewindings is controlled by a pilot switch.

One objectof the present invention is to provide a system of apparatus of the above noted class which shall include relatively simple and reliable means t'or preventing the 4e'ne'rgization of thel solenoid windings after current has once heen cut oti Jfrom the motor, until the current generated by the motor when it is short circuited upon itself, has fallen to a predetermined and relatively small amount.

Another object of the invention is to pro videa system of apparatus of the class above. indicated which shall include blow .out magnets for certain of the switches, and

`Ielectronia; {netic motor controlling switches and in which the arrangement of parts is i sli'ch that two windings are energized when the motor is short circuited on itself and therefore keep open the circuit of the main switch controlling solenoids until the speed of the motor and therefore the electroniotive force generated by it has fallen to a predetermined and relatively low point.

These ohjects and other .advantageous ends -I secure as hereinafter sct forth, reference heilig had to the accon'ipanyiiig drawings in which r:-

Figure l, isa t'ront elevation of a combination of apparatus arranged and constructed according to my invention; Fig. 2, is a vertical section illustrating the detail construction of a part ofthe apparatus shown in Fig. 1; Fig. 3, is a side elevation v"of the apparatus shown .in Fig. 1*;'F ig.4, is

Specification of Letters Patent.

Application 1ed `February 21, 1 910.

Patented Sept. 12, 1911.

Serial No. 545,134.

a diagrammatic view illustrating the electrical connections of the apparatus shown in Fig. 1; Fig. 5, is a frontelevationof a modified arrangement of apparatus, and, Fig. 6, is a modified view ofone of the switches employed by me.

In Figs. 1 to 4 inclusive, 51 represents a metallic frame or casing on which is mounted a slab o r plate 52 of insulating material, serving as'a support for the apparatus hereinafter described. i ratiis consists of a number of iron clad solenoids, in the present instance four, arranged in of two each. Of these solenoids, those lindicated at land @have their iron casings. connected by pole pieces 53 and 54 and have mounted between and slightly i-ii front of them, a blow-out inagnet 55 whose core forms part of the inagnetic circuit including said pole pieces and casings. Similarly, the other pair of solenoids, indicated at (i and 7, have a common blow out magnet 8, whose corelikcwise iorins part ot a magiietic'eircuit including their casings and pole pieces 9 and 10. The four solenoids have windings, indicated respectively at 1` 2, (la, and 7, and cores l", 2, (ih and 7b, which are longitudinally movable within said windings. `As shown in Figs. l and 3, each solenoid. casing has centrally mounted in its upper end a plug 11 through which passes a rod 12 rigidly fixed to and forming an extension of its core, and there is a spring 13 mounted. between said core and said plug. whereby the former is prevented from sticking to the plug and is promptly returned to its lower position when the solenoid winding is deinergized.

lllectrically connected to each rod 1Q is a y flexible conductor 14 forming under operating conditions some portion of the iiiain motor circuit and the various contacts 15,.

these two cores are mounted fixed contacts Q3 and 24, so placed to be engaged by the contacts 2c and GUM/hen the cores cari iner bthem are in their lower positions.

' The cores lland Il" of the solen'oids 1 and 7, when in` their lower positions, are capable of engaging spring mounted contacts 25 and 2G, each otl which has projecting `from it a spring 27 to which is fixed an auxiliary contact 28. A second auxiliary contact 29 is mounted on an arm 3() in such manner that after either of the cores 1' or 7", as the ease may be, has fallen to its lower position so as to engage 011e of the contacts 25 or 2G, the contact 28 is moved into engagement with the contact 29.

iVithin the magnetic circuits of the t-wo blow out magnets 55 and 8, I place switches, which may be of the construction shown in Figs. 3 or G in the first of which the switch consists of an iron contact 31 carried on a spring arm 32 in such position as to be drawn toward the blow out magnet pole piece below which it is -placed when said magnet is energized. Then said blow out magnet is denergized, this Contact 31 rests in engagement with the contact 33, and as shown in Fig. 4 these two switches are con nected in multiple between 011e of the supply mains and one end of the two solenoid windings 1 and 7 g the arrangement being such that if either of the blow out magnets is energized the corresponding contacts 31 and 33 ot' one of' the auxiliary switches are separated while current is free to fiow through the other of the switches, though it both of the blow out magnets be energized both of said switches are opened and energization of either of thel solenoid windings is impossible. To render clearer the illust-ration, the solenoids and certain of thev switches are shown in Fig. 4 in positions differing from those in which they are shown in Fig. 1.

In case it should be found that the auxiliary switch shown in Fig. 3 is abnormally sensitive, I may arrange it as shown in Fig. 6, in which an iron armature 31a is mounted to operate within the windinga of the blow out magnet adjacent the end et the core thereot', which is cnt ofi' short for this purpose. The spring contact arm or cur- -rent conductor 32 is as before connected to this contact piece and there 1s a fixed contact 33 so placed as to be engaged by said armature contact as long as the blow out magnet is denergized.

Two switches 34 and 35 are provided for adjusting by hand the two field rheostats whose resistance is indicated at 4 and 5 and at any convenient point there is located a pilot switch, indicated in Fig. 4, which is provided with two segmental contacts 36 and 37 connected by a body ot insulating material so as to be movable together. The first of these contacts is capable of electrically connecting a central contact 38C' with either of two side' contacts 39 or 40, while the other of said contacts is similarly capable ot connecting either ottwo contacts 41 or 42 with a central contact 43.

Under operating conditions the apparatus is connected to an electric motor as i1 `dicated at Fig. 4; the armature of said moto'r being shown at 44 and its armature resistance at 45. It the pilot switch is so operated that its contact 37 is made to connect4 the two contacts 41 and 43 and its contact 3G is at the ine time caused to connect contacts 38 and athen current flows from the supply main A through contacts 38, 3G and 40, etc., the winding 7a of the solenoid 7, and assuming that the motor is at rest, from the opposite end ot' this winding ,through one or both of the switches 33-31 and back to the supply main B; it being noted that previous to the operation of the pilot switch current is permitted to flow through the field winding 3 of the motor from the current supply main A, winding of blow out magnet 8, the switch. 20-23 and back to the main B. The energization of the winding 7 of the. solenoid 7 causes the core 7b to be raised that its contact 18 is brought into engagement with the contact 22, with the result that current is free to flow from the current supply main A through the blowout magnet 8, contact 25, core 1b, motor armature 44, all of the resistance 45, core 7", contacts 18 and 22 and so back to the main B. The motor is thus caused to start and as soon as its counter electric force rises to a predetermined point, there is sufficient current [iow from the said armature through the winding 6a. of the solenoid (S to cause the coreot said solenoid to be 'raised and its contact 17 to engage the contact 21'. )ne section-ofthe resistance 45 is thus short circuited, speeding up the moto'r and thereby causing such an increase of its counter electric motive force as will in turn cause the winding 2a of the soienoid 2 to be energized s'utiiciently to raise its core 2b; the successive action of the two solenoids 2 and 6 being insured by connecting in circuit with their windings bodies of resistance 4G and 47 of unequal amounts. The raising ot the core 2b breaks the connection between the contacts 2c and 23 so that the body of resistance 4 is placed in series with the field winding3; the current then flowing from the main A through the blow out magnet 8, contact 25, core 1", contacts 28 and 29, resistance 4 and field winding 3, to the main B. rlhis weakening of the field still further speeds up the motor and immediately thereafter the contact 1G comes into engagement with the contact 20 thereby short circuiting the remainder ot the armature resistance 4.3 and bringing themotor up to full speed. It will be noted that while the blow out magnet 8 is energized and therefore holds open the switch 3&31 which it controls. the other auxiliary switch is unaected and being closed permits the current flow to the solenoid 7% It now the pilot switch be' moved to its ott position as in Fig. 4, the three solenoid cores 2b, 6b, and 7b at once drop to their lowest positions thus bringlng the field ot the motor back to its maximumvstrength and at the same time chort circuiting the armature of the motor on itself ;-the current flowing from said armature to the core l, contact 25, blow out magnets S and 55, contact 26, core 7b, and back to said armature through resistance 45. The motor is thus caused to generate current and the revolution of the armature is quickly stopped according to the well known laws.

It will. lbe noted that even if the pilot switch be moved from its ott posit-ion to either of its on positions, current cannot be delivered to either ot the solenoid windings la or 7 because both of the switches 33-31 are held open by reason of the energization of both of the b-low out magnets 55 and 8, by the generated current. Then this has fallen to a predetermined small amount,

the cont-actsI 31 are released and under the- .that occurring when the solenoid 7 is energized. In every case, however, the motor cannot be started if both of the blow out magnets be energized and with the arrangement of parts shown this condition will ocv cur whenever the motor armature is short circuited on itself. The field current still comes to the blow out coil 8 when the solenoid l is energized until the solenoid 2 is energized.

In some cases I may dispense with the solenoid G and combine the other three solenoids with the two blow out magnets in the manner indicated in Fig. 5. In such case the casing of the intermediate solenoid is notl an essential part of the magnetic circuit of the blow out magnets although each of the outer solenoid casings is provided wit-h pole. pieces 50 connected to the blow out magnet cores and to each other bytransverse polev pieces as before. v

It will be understood that when the solenoid l is energized, the body 5 of field resistance is placed in circuit with the field winding 3` and as the amount of this resistance as well as that indicated at 4 may be varied by shi r" ting the movable contacts over the fixed contacts 34 ,and 35, it is obvious that the motor may be caused to operate at any desired different speeds when it turns in opposite directions.

From the above description it` will be noted ,that I have utilized the blow out magnets, which are necessarily L rovided for the various switch contacts, as the means for operating the auxiliary switcheswhereby flow of current to the reversing switch solenoids l and 7 'is governed. It 1s moreover to be noted that with the arrangement of wardly by its solenoid core in order to bring together said ltwo contacts 28 and 29. .This sequence of making and breaking contacts I have found to give the niost satisfactory results in the operation ofthe motor controlled by the above described apparatus.

By the particular arrangement and construction of the auxiliary switch shown in Fig. 6, the operation of the device is renderedcertain without being so sensitive as to operate at the wrong time.

I claim l. A motor controlling system-consisting ofmeans for governing the flow of current to the motor including a. plurality of electromagnetic main switches connected to serve as a reversing switch; a plurality of blow out magnets for said switches; with auxiliary switches controlled by the blow out magnets and connected to prevent the supply of current to the windings of the electromagnets :tor said main switches until the current in the blow out magnets has fallen to a predetermined extent.

2. A motor controlling system4 consisting of means for governing the llow of current to the motor including a plurality of electromagnetic main switches; a plurality of blow out magnets for said switches; with auxil-l iary switches respectively controlled by the blow out magnets and connected to control the supply of current to the windings of the electromagnets for said main switches; said auxiliary switches being connected in multiple and said blow out magnets being connected to be simultaneously energized only when the motor is short circuited on itself.

3. A motor controlling system consisting of means'for governing the flow of current to the motor and including an electromagnetic reversing switch; two blow out magnets for said reversing switch; with two [auxiliary switches respectively controlled by/ said blow out magnets and connected in circuit with the windings of the reversing switch to prevent low of currenty thereto until the' current in the blow out magnets has fallen to a predetermined extent. l

4. A motor controlling system vconsisting of a pair of fixed contacts connected to each other and to a current supply main; two movable members normally engaging said contacts respectively; a motor having YVits armature connected between said movable members; a second pair of ixed contacts connected to each other and to a second cur' -5. A motor controlling system consisting' of means Jfor governing the supply of current to the motor including a reversing switch having two actuating solenoids with contacts and connections arranged to short circuit the motor under predeterminedconditions; blow out magnets for the reversing switch; two auxiliary'switches connected in multiple to each other and respectively controlled by saidblow out magnets; said auxiliary switches being connected between the windings of the solenoids and one of the current supply mains; with a pilot switch connected to control the flow of current to the solenoids.

6. A motor controlling system consisting of means for governing the liow of current to the motor. and including an electromagnetic reversing switch having two solenoids; two blow out magnets for the reversing switch having connections whereby but one of them is energized when current is supplied to the motor; auxiliary switches respectivelyyeontrolled by said blow out magnets and connected in multiple with each other, said switches being in circuit with the windings of the solenoids; the system including means for short circuiting the motor on itself, and

die blow out magnets being connected to both to be 4energized when the motor is so short circuited.

7. A motor controlling system' consisting of a.r plurality of electromagnetic switches and the necessary connections therefor; one of said switches consisting oi two movable contacts; with a second switch having one ot its contacts yieldingly connected to one ot the movable contacts of said first switch; and meansfor yieldingly supporting the second contact of said switch.

Q8. The combination in a motor cont-rolling system ofI means for governing the current flow to the motor; including a solenoid; a switch having one. of its members connected to thc core of the solenoid; means for movably supporting the second member of said switch; and a second switch having one ot its members yieldingly connected to the sec ond member oit said tirst switch.

9. The combination in a motor controlling system of means 'for governing the supply ot current to the motor including solenoid; a switch governed by said solenoid and having one of its members connected to the core thereof; means for vieldingly supporting the second member oil' the switch; a second switch having a contact yieldinglv connected to said second switch member and a second contact for said second switch also having :L yielding support.

In testimony whereof7 I have signed my name to this specilication; in the presence of two subscribing witnesses.

SAMUEL 'llINE KEEFER.

Witnesses Gno. B. lVnAN, C. lV. Bnrrnn.

Copies of this patent may b obtained for five cents each, by addressing the Commissioner of Iatents,

Washington, D. C. 

